(2) Types of pollen and the process of pollination

What is pollination?  What are the types of pollination?

Types of pollen

For insect-pollinated flowers, the pollen grains produced are larger in size, sticky and spiny, which helps the insect to carry the pollen grains i.e. more likely to stick to the insects legs and body.

For wind-pollinated flowers, the pollen grains produced are smaller and lighter in weight, which can be carried by the wind easily.

 

Types of pollination

Pollination involves getting the male pollen from the stamen to the female parts of the flower.

The pollen transfer is specifically from the 'male' anther to the 'female' stigma.

After that, the male and female sex cells (gametes) must somehow fuse in the fertilisation process.

There are various types of pollination and plants display various evolutionary adaptations to aid the pollination process.

Apart from wind blow pollination, there is a wide variety of animal pollinators. These include birds, bats, butterflies, bees, moths, flies, beetles, wasps, small mammals. Many insects visit flowers to drink nectar or feed off of pollen and transport pollen grains as they move from plant to plant.

 

Self-pollination

Self-pollination is when the pollen grains are transferred from the anther of a flower to the stigma of the same flower (or a different flower on the same plant).

 

Cross-pollination

Cross-pollination is when pollen is transferred from the anther of one flower of a plant to the stigma of a flower of different plant by some means or other - details below.

 

Two typical ways in which cross-pollination takes place and evolutionary flower adaptations

Insect pollination

Many plants depend on insects to pollinate them and without the intervention of bees, moths and butterflies, many species of plants would struggle to reproduce. This has implications for the food chains from which we derive our own food, if pollination is disrupted, so is our food supply, so the more bees, moths and butterflies we have, the better for our ecosystems including our food supply.

Nectaries are specialised glands of the flower near the base of the carpel that produce a sugary liquid which functions as an attractant (a “reward”) to promote animal pollination, usually by flying insects.

When an insect like a bee alights on the flower seeking food, some of the pollen sticks on to the insect from the stamen and carried away with the insect. When the same insect visits another flower, some of the male pollen brushes off onto the female stigma of another flower, potentially allowing fertilisation to take place.

 

Flowering plant adaptation features for insect pollination include:

(i) brightly coloured petals,

(ii) scented flowers,

(iii) nectaries to supply the insect with food (see above).

(iv) A sticky surface on the stigma to increase the chance of pollen grains sticking to it.

I've recently learned that nighttime moths are just as effective pollinators as daytime bees and butterflies. Don't swat the moths, they are good for us all, and in the UK there are far more species of moths than are butterflies!

 

Wind pollination

Pollen grains are usually tiny and very 'light' in weight, and so easily carried away by wind. So the natural movement of air carries away pollen from the stamen of one plant to the stigma of another plant.

Flowering plant adaptation features for wind pollination include:

(i) usually small dull in colour (attracting insects is not a priority),

(ii) no scent or nectaries (attracting insects is not a priority),

(iii) long filament hang the anthers outside of the flower so pollen is more easily blown away by wind,

(iv) stigmas are feathery in structure, more like a 'net' system, to capture the pollen grains floating by in the air.

---

Key points on types of pollen and modes of pollination

Source of information is based on textbooks and syllabus-specifications for students taking the AQA GCSE, Edexcel GCSE and OCR GCSE level biology examinations (~US grades 9-10)

---

Pollination in Flowering Plants

Pollination is the transfer of pollen from the anther (male part) to the stigma (female part) of a flower. This is a vital step in sexual reproduction in plants.

---

Types of Pollen

Pollen grains vary depending on the method of pollination:

1. Insect-Pollinated Pollen

• Large, rough or sticky grains

• Designed to cling to insect bodies (e.g. bees, butterflies)

• Fewer grains needed because insects efficiently transfer pollen

• Typically produced by brightly coloured flowers with scent and nectar

2. Wind-Pollinated Pollen

• Small, smooth, and lightweight

• Produced in large quantities to increase chances of reaching another flower

• Easily carried by the wind

• Produced by flowers that are small, dull, with no scent or nectar

---

Types of Pollination

1. Self-Pollination

• Pollen is transferred to the stigma of the same flower or another flower on the same plant

• Less genetic variation produced

• Advantage: doesn’t rely on external agents

2. Cross-Pollination

• Pollen is transferred between flowers of different plants of the same species

• Introduces genetic variation, making offspring more adaptable to environmental changes

---

Methods of Pollination

Pollination Method	How It Works	Key Adaptations of the Flower
Insect Pollination	Insects visit flowers for nectar; pollen sticks to their bodies and is transferred to the next flower	Bright petals, scent, nectar, sticky/stiff pollen, anthers and stigma positioned to brush against insect
Wind Pollination	Wind carries pollen from one flower to another	Dull colours, no scent/nectar, long feathery stigmas, exposed anthers, large quantities of pollen
Water Pollination (less common)	Pollen floats on water from one plant to another	Aquatic plants produce waterproof pollen
Animal Pollination (e.g. birds, bats)	Animal feeds on nectar or fruit and transfers pollen	Large flowers, strong scent or vibrant colours, pollen sticks to fur or feathers

---

Summary

• Pollination is essential for fertilisation and seed production.

• Different flowers are adapted to different pollination methods.

• Pollen structure and quantity vary greatly depending on how it’s dispersed.

---

Keywords, phrases and learning objectives for this part on flowering plants

Know and be able to describe the types of pollen and types of pollination in flowering plants.

Be able to describe the adaptations including self-pollinating flowering plants and cross-pollinating flowering plants.

Be able to describe pollen transfer in terms of insect pollination, wind pollination and adapted features to aid pollination.

---

WHAT NEXT?

TOP OF PAGE

INDEX of biology notes on flowering plants

INDEX of all my BIOLOGY NOTES

BIG website, try using the [SEARCH BOX], maybe quicker than the many indexes!

Basic Science Quizzes for UK KS3 science students aged ~12-14, ~US grades 6-8

Biology * Chemistry * Physics for UK GCSE level students aged ~14-16, ~US grades 9-10

Advanced Level Chemistry for pre-university age ~16-18 ~US grades 11-12, K12 Honors

Find your GCSE/IGCSE science course for more help links to all science revision notes

email doc brown - comments - query?

---

Revision notes on describing types of pollen based on the syllabus-specifications for students taking IGCSE/GCSE level biology examinations, summary revision notes and key points on describing types of pollen for students taking the AQA igcse/gcse biology notes on describing types of pollen, Edexcel gcse biology notes on describing types of pollen,  OCR 21st century GCSE biology notes on describing types of pollen, OCR gateway GCSE biology notes on describing types of pollen, WJEC gcse biology notes on describing types of pollen, CCEA gcse biology notes on describing types of pollen for students taking CIE Cambridge igcse biology, exam revision notes on describing types of pollen, useful for US grade 9-10 biology courses, importance of explaining how pollination takes place in GCSE level biology, What you need to know about explaining how pollination takes place for GCSE level biology, Explaining the use of explaining how pollination takes place knowledge in GCSE level biology, Examples of explaining how pollination takes place explained when studying GCSE level biology, What is significant about explaining how pollination takes place, describing the theory of explaining how pollination takes place when studying GCSE level biology, revision notes for explaining how pollination takes place in exams, online exam help for explaining how pollination takes place, revision notes about explaining how pollination takes place, what do I need to learn about explaining how pollination takes place for by GCSE biology exam? help to understand the explaining how pollination takes place topic in preparation for GCSE biology exam question, how to prepare for questions involving explaining how pollination takes place in a GCSE biology examination?

---